1. Field of the Invention
The present invention relates to an all-solid-state lithium-ion secondary battery and a production method thereof.
2. Related Background Art
A lithium-ion secondary battery is composed mainly of a cathode, an anode, and an electrolyte layer disposed between the cathode and the anode (e.g., a layer consisting of a liquid electrolyte or a solid electrolyte). In the conventional secondary batteries, the cathode and/or the anode is made using a coating solution (e.g., a solution of a slurry form or a paste form) for formation of the electrode containing an active material for the corresponding electrode, a binder, and a conductive aid.
A variety of research and development has been conducted on the lithium-ion secondary batteries toward further improvement in battery characteristics so as to adapt for future development of portable equipment (e.g., achievement of a higher capacity, improvement in safety, increase in energy density, and so on). Particularly, as to the lithium-ion secondary batteries, an attempt to realize a configuration of a so-called “all-solid-state battery” employing an electrolyte layer consisting of a solid electrolyte is being made from the viewpoints of achieving weight reduction of the battery, increase in energy density, and improvement in safety.
However, the solid electrolyte provides high safety on one hand, but has a problem that it is inferior in rate characteristic to the electrolyte solution because of the smaller number of ion-conduction paths, on the other hand. For remedying this problem, there are the following proposals of production of the all-solid-state battery: a method of forming the solid electrolyte layer by vacuum evaporation (see, for example, Japanese Patent Application Laid-open No. 2004-183078); a method of impregnating a solid electrolyte and an electrode with a polymer solid electrolyte and polymerizing it (see, for example, Japanese Patent Application Laid-open No. 2000-138073), and so on.